Treatment of ferrous metals



April 16, 1935. w. R. BEN NETT r 1,997,557

TREATMENT OF FERROUS METALS Filed June 20, 1934 INVENTOR.

WZZar E BY M@@ ATTORNEY.

Patented Apr. 1 6, 1935 UNITED STATES PATENT OFFIE 7 Claims.

This invention relates to improvements in apparatus for treating metals and is directed more particularly to furnace apparatus for heating metals of all kinds in connection with tempering, drawing, case-hardening, and all types of other metal treating operations.

One important object of the invention is directed to the provision of a furnace apparatus which has a. single chamber arranged and adapted to function as a combined combustion and heating chamber making it possible thereby to obtain the desired operative temperatures which may be maintained uniformly in an efiicient manner and at low operating cost.

Another object of the invention is the provision of a furnace apparatus wherein the work to be treated is not only encircled by the products of combustion to provide the desired uniformity of temperature but the work being heated is not impaired by the products of combustion. This is accomplished by the provision of a novel chamber as will hereinafter appear.

A further object of the invention is the provision of a furnace of the type referred to which is not only simple in form but which is efiicient in its operation, while by reason of its novel construction and arrangement heating operations are performed with a minimum of. fuel consumption.

Various other novel objects and advantages of the invention will be hereinafter more fully referred to in connection with the accompanying description of the present preferred form thereof, reference being had to the accompanying drawing wherein:

Fig. 1 is an elevational sectional view through the furnace embodying the novel features of the invention;

Fig. 2 is a sectional plan view on the line 2-2 of Fig. 1 to show certain details of construction;

Fig. 3 is an inverted plan view of the cover members of the furnace shown in Fig. 1, and

Fig. 4 is a plan view of a part forming the lower side of the combustion and heating chamber.

Referring now to the drawing more in detail the invention will be fully described.

A base is provided at 2 which may be of any suitable form. In the form of the invention shown, this base is adapted to support the structure. An outer shell member 4 is provided which is preferably of metal to function as a casing and a lowermost wall member 6 is provided which may be of insulating or in some cases refractory material. The member 6 rests on the base 2.

A member 8 on the wall member 6 is preferably of refractory material. This member 8 as well as the member 6 and the base 2 are provided with openings therethrough substantially as shown to form an inlet II! for fuel.

The upperside of member 8 is provided with a plurality of slots or grooves 9, three of such slots being shown, and ledges or inserts (2 which may be of silicon-carbonate are receivable in the slots 9. These extend inwardly into a more or less cup-shaped depression or well [4 provided in the member 8, the said depression serving as the lower part of a chamber 20 as will appear.

A deflector plate 16, preferably provided with a lower tapering side as shown, is supported by the ledges l2. The peripheral edge of this plate 16 is spaced from the sides of the depression id in the member 8 to provide an annular passageway therearound. Above the member 8 and in alignment with the depression l4 thereof and as a continuation thereof refractory material in dicated at 22 is provided and this forms the central chamber 20 and provides a single combustion and heating chamber.

It will be noticed that the chamber is formed to have walls which are concaved or that swell outwardly intermediate the upper and lower sides of the chamber. The reason for this will presently appear.

Other refractory material 24 is located above the material 22 and has an opening 25 therethrough which may be called a flue. Insulating material indicated at 26 is disposed around the members 8 and 22 which may serve to hold the refractory material in position as well as to 'msulate the structure. A cover indicated at 28 is disposed over the top side of the furnace, as shown. This cover may be of metal and circular in form or in some cases if desired the cover may consist of a plurality of separate members,

Cover members 30 over the opening 26 preferably consist of a pair of semi-circular plate members such as shown in Fig. 3. These are arranged to have a central opening 32 therethrough and are provided with handles 34 to facilitate easy and ready manipulation thereof. These covers may be made of refractory material or whatever may be desired.

A plate 40 is provided which is preferably of refractory material and it has its marginal edges spaced from the walls of the chamber. This plate 40 preferably rests on spacers 42 which may be blocks supported by the member [6 or they may take the form of legs associated with the plate $2. I have found it desirable to have the member 40 spaced upwardly somewhat from the deflector member it for reasons to later appear.

Various fuels may be used in connection with the furnace of the invention such as for instance oil, gas, or the like. A fuel burner of ordinary form is represented at 50 which has fuel and air lines 52 and 54 associated therewith. With the proper mixture of fuel and air delivered to the inlet ill of the furnace various heating or metal treating operations may be performed. The furnace is constructed and arranged to facilitate work being suspended in the chamber 20.

The products of combustion pass upwardly through the space between the marginal edge of the deflector plate I 6 and the wall of the chamber which is a decided advantage because the work being heated is surrounded by the products of combustion. It is not only heated uniformly thereby but it is not subjected to the products of combustion directly so that it is injuriously affected thereby. Where the work is subjected directly to the products of combustion, various chemical and physical reactions occur which I avoid. The products of combustion travel upwardly and closely adjacent the concave or swelling inner wall of the chamber and upwardly and over the work and then outwardly through the outlet and outlet 82 between the cover members 30.

In this way, the work is surrounded by the products of combustion by which it is heated without being subjected to direct contact therewith. This is a decided advantage in respect to uniformity of heat and attendant results.

The cover members may be moved relative to one another to vary the sine ofthe opening 32 therethrough so as to regulate and control the action of the apparatus which is always to be desired.

An opening 54 is provided in the side of the furnace for receiving a part of a pyrometer or other temperature responsive indicating device. It will be readily apparent that where the work is located centrally of the chamber that the end of the pyrometer element may be located closely adjacent to the work so that a temperature reading more nearly corresponds to the actual temperature of the work than to that of the products of combustion.

In some cases it may be desirable to locate a pot within the furnace as where a bath is to be used. To facilitate this a plug 56 is provided which is removable from a suitable opening in a side of the furnace. The plug will preferably be of refractory material and when a pot is inserted in the chamber the opening provided for the plug will serve as a flue so that the products of combustion may pass upwardly and outwardly from the furnace.

The member 42 functions to equalize and reduce the temperature at the lower part of the chamber 10. Direct heat impinging the member I6 is likely to elevate the temperature in the lower part of the chamber. The member 40 however spaced from member 16 has been found to efficiently reduce the temperature at the lower side of the chamber so that substantially the entire chamber is heated uniformly which insures uniformity of temperature for the work being heated.

It is desired to point out that the opening receiving the plug member 56 may be utilized for the inserting of work in the chamber. Often times it is desired to heat a part of a piece of work and this is facilitated by the side opening.

It will be observed that I have provided a furnace which is simple in form so as to be economical to manufacture and by reason of its novel construction it is adapted to efficiently and economically operate for the heating of metals of all kinds. It will also be observed that the chamber is constructed and arranged to serve as a heating and combustion chamber to facilitate the obtaining of uniform and constant temperatures without liability of the work or the heating operation being impaired by direct contact of the products of combustion with the work. As has been explained, the products of combustion pass upwardly adjacent the concaved wall of the combustion chamber and then over the work within the chamber so that the work is enveloped by but is not disposed in the path of the flame.

Various changes and modifications may be made in the form of the invention without departing from the spirit and scope thereof in its broader aspects. Therefore I prefer to be limited, if at all, by the appended claims rather than by the foregoing description. What it is desired to claim and secure by Letters Patent of the United States is:

1. A furnace of the class described comprising in combination, members forming a combined combustion and heating chamber with a fuel inlet at the lower side thereof and an outlet at the upper side thereof, a deflector substantially horizontally disposed adjacent the lower side of the chamber having its marginal edges spaced from the adjacent walls of the chamber to provide an annular passageway to direct products of combustion upwardly adjacent the walls of said chamber, the lower side of said deflector plate being inclined inwardly and downwardly from the marginal edges thereof towards the center of said deflector plate, and a plate above said defiector plate and spaced therefrom having its marginal edges spaced from the wall of the chamber.

2. A furnace of the class described comprising in combination, a wall of refractory material forming a substantially vertically disposed combined combustion and heating chamber having a fuel inlet at its lower side and an outlet at its upper side, ledges extending inwardly from the sides of the chamber adjacent said lower inlet, and a deflector plate supported by said ledges having its marginal edges spaced from the walls of the chamber to direct products of combustion upwardly along the walls of the chamber, the inner wall of said chamber being concave whereby the chamber is of greater area intermediate its upper and lower sides than at said upper and lower sides.

3. A furnace of the class described comprising in combination, a support, a lower member having a depression therein forming the lower part of a chamber, and provided with a fuel inlet leading into said depression at the lower side thereof, a wall of refractory material above said member formed to provide a continuation of said depression and co-operate therewith to provide a combined combustion and heating chamber open at its upper side, the walls of said chamber being concaved between the upper and lower sides thereof, ledges extending inwardly at the lower part of said chamber over said inlet, a deflector plate on said ledges having a lower side which inclines inwardly and downwardly from the marginal edges thereof, said edges being spaced from the said walls of said chamber to provide an annular passageway therebetween for directing products of combustion along and adjacent the walls of the chamber.

4. A furnace of the class described comprising in combination, a support, a lower member having a depression therein forming the lower part of a chamber and provided with a fuel inlet leading into said depression at the lower side thereof, a wall of refractory material above said member formed to provide a continuation of said depression and co-operate therewith to provide a combined combustion and heating chamber open at its upper side, the walls of said chamber being concaved between the upper and lower sides thereof, ledges extending inwardly at the lower part of said chamber over said inlet, a deflector plate on said ledges having a lower side which inclines inwardly and downwardly from the marginal edges thereof, said edges being spaced from the said walls of said chamber to provide an annular passageway therebetween for directing products of combustion along and adjacent the walls of the chamber, and a plate spaced above said deflector plate having its marginal edges spaced from the walls of the chamber to form an annular space therebetween to permit products of combustion to flow therebetween.

5. A furnace of the class described comprising in combination, a support, a lower member having a depression therein forming the lower part of a chamber and provided with a fuel inlet leading into said depression at the lower side thereof, refractory material above said member formed to provide a continuation of said depression and co-operate therewith to provide a combined combined combustion and heating chamber open at its upper side, the walls of said chamber being concaved between the upper and lower sides thereof, ledges extending inwardly at the lower part of said chamber over said inlet, a deflector plate on said ledges having a lower side which inclines inwardly and downwardly from the marginal edges thereof, the said Walls of said chamber to provide an annular passageway therebetween for directing products of combustion along and adjacent the walls of the chamber, and a plate spaced above said deflector plate having its marginal edges spaced from the walls of the chamber to form an annular space therebetween to permit products of combustion to flow therebetween and relative movable cover members over the upper side of the chamber having an outlet associated therewith which is variable by relative movements of said cover members.

6. A furnace of the class described comprising in combination, a lower wall of refractory material having a depression therein open at its upper side and provided with a fuel inlet leading thereinto, a wall of refractory material thereabove formed to provide a chamber above the depression having side walls curving upwardly and outwardly from said depression and then inwardly forming a central outlet at the upper side thereof of less diameter than the diameter of the chamber intermediate its ends, the said chamber intermediate its ends being greater in diameter than the diameter of the depression, and a deflector disposed adjacent the jointure of the walls of the depression and chamber having its peripheral edge spaced therefrom to form with said walls an annular passageway for directing products of combustion from said depression upwardly and outwardly against the side walls of the chamber.

'7. A furnace of the class described comprising in combination, a lower wall of refractory material having a depression therein open at its upper side and provided with a fuel inlet leading thereinto, a wall of refractory material thereabove formed to provide a chamber above the depression having side walls curving upwardly and outwardly from said depression and then inwardly forming a central outlet at the upper side thereof of less diameter than the diameter of the chamber intermediate its ends, the said chamber intermediate its ends being greater in diameter than the diameter of the depression, a deflector disposed adjacent the jointure of the walls of the depression and chamber having its peripheral edge spaced therefrom and provided with an inclined lower side to form with said walls an upwardly converging annular passageway for directing products of combustion from said depression upwardly and outwardly against the side walls of the chamber, and a. plate spaced above the deflector plate having its edge spaced from said walls to form therewith a passageway continuing from the first-named passageway.

WILBUR R. BENNETT. 

